OVERVIEW OF THE IMMUNE SYSTEM
LYMPHOCYTE SUBPOPULATION IN HUMANS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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T lymphocytes that recongize self-antigens are allowed to survive; T lymphocytes that do not recognize self-antigens are neglected and die
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Positive selection
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Negative selection
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Either A or B
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None of the above
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Explanation:
Detailed explanation-1: -Lymphocytes come from the bone marrow. However, only B lymphocytes are educated and mature here. T lymphocytes must travel to the thymus to mature. It is here that they are taught to recognize self (our own cells/antigens) from non-self (viruses, bacteria etc.).
Detailed explanation-2: -Negative selection occurs when double positive T cells bind to bone-marrow derived APC (macrophages and dendritic cells) expressing Class I or Class II MHC plus self peptides with a high enough affinity to receive an apoptosis signal.
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